Automatic safety attachment for pneumatic hammers



June 1 1926. 1,586,865

CL B-VVAIJE AUTOMATIC SAFETY ATTACHMENT FOR PNEUMATIC HAMMERS Filed March 1923 Q 2 Sheets-Sheet l June 1 ,1926. 1,586,865

C. B. WADE AUTOMATIC SAFETY ATTACHMENT FOR PNEUMATIC HAMMERS Filed March 12, 1923 2 Sheets-Sheet 2 0/3. Wade f, 6cm

Patented June 1, 1926 UNI- T ED STATE SI.

OFFICE; i

GHARLES'B. warmer noanomz, VIRGINIA...

AUTOMATIC SAFETY ATTACHMENT FORE PNEUMATIC HAMMERSL.

I ApplicationlfiledrMarch 12, 1923. Serial No, 624,601.

It often happens that the starting-trigger,- is accidentally pressed, when the hammer is.

not in use and this causes the tool or bit to fly out causing.;.,injuries to bystandersand the main object of the invention is now' to provide an attachment for pneumatic hammers that will prevent such accidents. This attachment can be applied to any hammer of this class with only slight alteration thereof, and atvery littlecost.

It is evident that by this arrangement not only the tool or bit will be prevented from flying out accidentally but also the plunger actuating the bit will be prevented from .doing-damage whether the bit is in position or not.

In the accompanying. drawings one e1nbodiment of the invention is illustrated, and;

Figure 1 represents a side elevation of a pneumatic hammer with the safety attachment installed thereon;

Figure 2 is a partial longitudinal section of the device taken along. line 2+2 of Fig ure 1;

Figure 3 is a transverse'section along line 3-3 of Figure 1;

' Figure 4c is a partial transverse section along line 44 of Figure 1;

Figure 5 is a-half longitudinal section and half elevation of a pneumatic hammer equipped withthis devicewhich is built into the housing of thehammer;

Figure 6 isa transverse section alongline 66 of Figure 5; and.

V Figure? is a transverse section alongline. 77 of F1gure5."

Referring first to the device .asillustrated inFigures 1 to 4, referencenumeral 1O represents the head of the housing of a pneumatic hammer of any modern construction a-ndprovided Witha handle 11 having a hose connection as at 12 and a valve trigger 13 for admitting the pressure fluid into the passage 14 in the handle. Ordinarily this passage opens directly into the central cavity of the housing to. act upon a reciprocating plunger which produces the blows on the tool or bit 15 at the forward or lower end of the housing. As shown in Figure 1, this bit isheldin position by a flexible clip16 Y to admit of the limited longitudinal motion of the bit 15, when positioned in the end of the housing. The bit is providedwith the usual shoulder 1 7T projecting radially beyondfthe shank 18," which. holds the: bit in positionin the housing. The features of the.

pneumatiohammer described so .far are simia lar in all such tools and form no partof the present invention;

The safety device consists of asubstam tially cylindrical casing. 19 having. a chamber 20 which is closed at its upper end by, a. threadedicap 21. Thechamber 20 tapers downwardly to form a seat22. for a valve 23 normally, seated. by ,means of a. coil spring.

24 surroundingvthe.valve spindle 25. The latter is guided at its upper end in the correspondingrecess 26' furnished 'inthe cap 21 and in orderthat the casing 19 may be made as short as possible the upper end of the coil spring2i is seated'in: a counterbore 27 furnished in thecap 21.

Below the valve seat 22, the chamber2O is slightly restricted as at 28 and opens into thetransverse passage 29. Below this .pas-n sage acentral bearing 30 is formed fo'r the valve-controlling'rod 31 and this bearing terminates: with" a threaded shank. 32 over which a packing nut 33 isEpla'ced, and. be-

tween the shankl'and the nut is furnished a.

suitable packing 34. In-this manner. a packing, box is furnished for the actuating rod 31.

The lower end of thelrod 31 terminates ingly threaded "extension. rod. 36 andfa lock.

nut 37 tightens the connection of the two rods. The addedlengthof the rodf31 and the extension rod 36 is such that when. the

bit 15 is in itsloweredlposition, as seenin Figure 1,.and the lower endof the extension-v rod 36 rests on the shoulder-.17," the upperv end of the rod .31 is slightly below the valve head 23, sothat. the seatingof the valve is: insured by ,the action of the coil :springl241 In .order to guidetheextension rod :36

a sleeve 38 is furnished and preferably se- Ordinarily the passage 14 in the handle 11 communicates directly with the chamber in the housing for directing the fluid pressure against the plunger, this communication takes place through a port 41 furnished in the upper end of the housing. It will now be necessary to drill an aperture 42 across this port 41, as best seen in Figure 3, and to divide this aperture by an inserted plug 43. The end of this aperture 42 nearest to the passage 14 has a port 44 to one side thereof, and between this port and the corresponding port 45 leading into the chamber in the casing 19 is inserted a piece of pipe 46 which is preferably spot welded to the casing as well as to the head of the housing, as best seen in Figure 3.

' The port 29 at the lower end of the casing 19 is similarly connected by means of a pipe 47 with the other end of the aperture 42, and this pipe is also spot welded both to the head 10 and the casing 19. It will thus be evident that when the valve trigger 13 is pressed, fluid will be admitted from the hose 12 through the passage 14 and through. the port 44, pipe 46 and port/45 into the upper end of the chamber 20. As the outlet 28 from this chamber is closed by thevalve 23 actuated by the coil spring 24, the fluid pressure can proceed no further until the valve is lifted by the pressing of the bit 15 against the work, when the shoulder 17 will.

press the extension rod 36 and the rod 81 upwards and lift the valve, whereupon the fluid pressure can proceed through the port 29 and the pipe 47 into the aperture 42 and through the port 41 to act'upon the plunger in the ordinary 'manner. evident that both the trigger 13 and the valve 23 have to be simultaneously actuated to operate the bit 15.

Referring now to Figures 5 to 7 inclusive,

these figures illustrate a pneumatichammer into which the safety device has been built from the start, so that no attachment therefor is needed. In this case the housing 50 has an eccentricduct as at 51 in which the valve-controlling rod 52 is mounted to reciprocate so that its lower end engages with the shoulder 17 of the bit 15 as previously described. This duct continues upwardly and opens into an annular groove 69 pro vided in a nut 53, in which the fluid passage 54 is furnished from the handle 55 of the hammer. A cap 56 is threaded into the top of'this nut 53 and is providedwith a side port 57 connecting with the passage 54.

It will thus be the upper end of the coil spring 61 and the V chamber 58 communicates downwardly with the eccentric bore or duct 51 which is enlarged, as at- 70, to form a port similar'to 29 in Fig. 2. From this port the pressure fluid is led through suitable conduits and delivered againstthe hammer in the usual manner.

The action of the parts is identical with that of the attachable safety device already described and no further description of the use and action of this complete pneumatic hammer is needed.

When in the claim, the term bit is used, this is meant to include any kind of punch, rivet set, or tool operated by a pneumatic hammer.

Having thus described the invention what is claimed as new is:

The combination with a housing h-avinga laterally extending inlet passage for pressure fluid in its upper endand having a pressure chamber below and closed to said passage, a tool in the lower end of the housing, and a valve-controlling rod in contact with the tool and extending longitudinally of the housing to a point between the inlet passage and the pressure chamber, of a valve chamber at the upper end of the housing eccentric to the pressure chamber receiving the upper end of said rod and extending longitudinally of the housing across and communicating with the end of said inlet passage, the valve chamber comn1uni-' eating through its lower end w1th the pres sure chamber and having a seat disposed between the said inlet passage and said pressure chamber, the inlet passage and the pressure chamber being out of communication except through the lower end of the valve chamber, a valve in said valve cham-' CHARLES B. WADE. 1.8. 

